Renault said fraud investigators were looking at the way it uses exhaust-emissions technology in an additional probe of parts and factories that follows an earlier investigation by the French government.

An official with the French Finance Ministry's anti-fraud unit confirmed it had conducted raids on Renault last week but would not elaborate on why. The official was not authorised to be publicly named.

After a probe by US investigators that began in September 2015, Volkswagen admitted to using the so-called “defeat devices” to conceal the level of toxic emissions from some of its diesel vehicles.

The German carmaker faces billions of dollars in claims from customers around the world with similar software installed in their vehicles.

Renault’s stock saw some 5 billion euros wiped from its market capitalisation in its worst day since the company was first listed in 1994, according to Reuters data. The shares pulled back from their losses after the statement to stand down 13.78 percent at 12:46 GMT.

Shares of fellow French carmaker Peugeot also tumbled, amid apparent suspicions that it was being targeted, too. PSA Peugeot-Citroën issued a statement saying that it had not been raided by anti-fraud authorities and that the French government tests on Peugeot-Citroën cars had found no anomalies.